Light emitting diodes (LEDs) or organic light emitting diodes (OLEDs) will increasingly be used for decorative purposes or for display applications. To have a high resolution and smooth transitions, a large number of light spots are required. In many of these applications, electronic circuits are used to control the LEDs, particularly the status (on/off) of the LED. As it is known in the art, the on/off condition can be controlled via a shunting switch which is coupled parallel to the respective LED. If the shunting switch is on (closed), the LED is shunted and, hence, off. If the shunting switch is off (open), the LED is on, since the drive current does not flow through the shunting switch. Beside the status (on/off) of the LED, its average brightness or light intensity may also be controlled by switching the shunting switch according to a predetermined or selectable duty cycle.
In all these cases, the control circuits require a power supply supplying the necessary energy. This requirement results in either additional wires to feed the supply voltage to the on-site control circuit or in a power supply which can derive its power from the LED supply. In most cases, the second solution will create additional losses or will have unwanted influence on the LED behavior.